Web hosting

The easiest and fastest way to clear Drupal’s cache if you have access to its database is to execute the following SQL query on its database:

DELETE FROM {cache};

Another way to clear the cache in Drupal is to create a PHP file to clear caches and rebuild the routing tables. Be careful not to leave this on the server as anyone can clear caches if they know the file name. Create a file named clear.php with the following code. Place the file in drupal base directory and run it by browsing to http://example.com/clear.php.

The third and the lamest way is through the Drupal’s admin area. Simply go to Administer > Site configuration > Performance. Near the bottom of the page, you’ll see a big fat button that says “Clear cached data.” I think you can take it from there.

RGP stands for Redemption Grace Period. The Redemption Grace Period is a thirty (30) day period that begins after a registrar requests that the registry delete a domain name. The Internet Corporation for Assigned Names and Numbers (ICANN) has required that registries implement this facility to allow the original registrants (domain name holders) to redeem a deleted name.

The reason for the introduction of the RGP process is to provide additional time to catch erroneous deletions before the name is made available for re-registration.

When a name enters RGP, it is removed from the zone file (if it was originally in the zone file). As a result, any Internet services served by the domain name will be disabled (e.g. e-mail or a Web site). The registrant must act IMMEDIATELY if he or she wants to keep the name.

You’ve registered your domain name, and paid for hosting with a hosting provider, and uploaded your website to the web server. If this is all done, why can’t you see the results of your hard work right away? What is this DNS propagation people keep telling you about?

In order to understand DNS propagation, you must first understand a little about how DNS works. When you set up your website with your hosting provider, they create a Master DNS record in their Domain Name Servers. Your domain registrar (the company you paid for the honor of owning your domain name) points to your web host’s DNS server as being the master authority of your domain.

When any outside source wants to know how to find your website, they first go to the registration database to find out who the DNS authority is for your website. Then they visit your hosting provider’s DNS servers to find out what the IP Address is for your domain name, and from there your audience can now view your website.

The problem with this whole scheme is that in order to speed up the rate at which their customers can view the internet, each Internet Server Provider caches their DNS records. This means that they make their own copy of the master records, and read from them locally instead of looking them up on the Internet each time someone wants view a website. This actually speeds up web surfing quite a bit, by (1) speeding up the return time it takes for a web browser to request a domain lookup and get an answer, and (2) actually reducing the amount of traffic on the web therefore giving it the ability to work faster.

The downside to this caching scenario and what makes it take so long for your website to be visible to everyone, is that each company or ISP that caches DNS records only updates them every few days. This is not any kind of standard, and they can set this time anywhere from a few hours to several days. The slow updating of the servers cache is called propagation, since your websites DNS information is now being propagated across all DNS servers on the web. When this is finally complete, everyone can now visit your new website. Being that the cache time is different for all servers, as mentioned above, it can take anywhere from 36 to 72 hours for DNS changes to be totally in effect.